Throttle operating mechanism for carburetor

ABSTRACT

A throttle operating mechanism adapted to open and close a carburetor throttle valve of an internal combustion engine, which mechanism has a throttle actuating arm rotatable with the throttle valve and biased in a direction to close the throttle valve by a first biasing means, and a dashpot cooperating with the throttle actuating arm, which dashpot is arranged to dampen the rotation of the throttle actuating arm and to release dampening effect to allow quick rotation of the throttle actuating arm to prevent running or dieselling of the engine.

United States Patent 1191 Hisatomi Nov. 12, 1974 [54] THROTTLE OPERATING MECHANISM 3.682.148 8/1972 ami o"; 123/198 DB FOR CARBURETOR 7 3,744,470 7/1973 clarkeim 123/198 DB 3,744,471 7/1973 Braun...., 123/198 DB [75] lnventor: Takashi Hisatomi, Tokyo, Japan [73] Assignee: Nissan Motor Company, Limited, Primary Examiner'--Charles J. Myhre Yokohama, Japan Assistant ExaminerR. H. Lazarus 221 Filed: June 5, 1973 1 [211 App]. No.: 367,151 1 1 STRACT I A throttle operating mechanism adapted to open and 30 Foreign li t priority Data close a carburetor throttle valve of an internal combustion engine which mechanism has a throttle actu- 72 June 6 19 Japan 47 6707] atmg arm rotatable with the throttle valve and blflSfiCl' s2] us. Cl. 11 123/198 DB 123/97 in a direction to clcse'the throttle Valve by first bias- 51 1 1m. F02 b 77/00 means and dashpot Cooperating with hrottle [58] Field of Search I l23/198 DB 198 R 97 R actuating arm, which dashpot is arranged to dampen "123/1316 H 103 R 103 the rotation of the throttle actuating arm and tore- I 7 lease dampeningeffect to allow quick rotation of the [56] References Cited throttle actuating arm to prevent running or dieselling UNITED STATES PATENTS Ofthe engme' I I j 7 2,692,651 10/1954 Ball 123/103 7 Claims, 3 Drawing Figlll tS IO 2 26 I r 28 IL 7 I w I 3Q 5 580 \22 [2 I \I-\ O Q r I 4 I 3 i 58 1 F a 1 520 g i v 1 I. \1 v I 1111' 52C 58b I \wn I 52b 9 52 PATENTEDNHY 12 1914 31847; 1 31 SHEET 10F 2 PATENTEDNUV 12 m4 SL847; l 31 sum 2 or 2 7 44 42 4&531 42o #72 420 Q THROTTLE OPERATING MECHANISM FOR CARBURETOR of the toxic compounds such as hydrocarbons and car-- bon monoxide in engine exhaust gases discharged into the atmosphere. In this prior method, it is desired that, in order to provide highly stability in idling operation, the engine speed be increased during this particular operating condition. This is reflected by the fact that a.

large smount of intake air flows through an engine carburetor and, therefore, the engine does not cease to operate in the shortest period of time even when an ignition switch of the engine is opened.

In the conventional internal combustion engine, it has also been proposed to have the carburetor equipped with a dashpot which functions to prevent a carburetor throttle valve from being closed too fast after an accelerator pedal is released for thereby effecting smooth deceleration of the engine. A drawback is also encountered with this dashpot in that the engine continues to run on or diesel even when the ignition switch is opened.

It is, therefore','an object of the present invention to provide a throttle operating mechanism for a carburetor of an internal combustion engine which mechanism eliminated the drawbacks encountered in the prior art.

a throttle operating mechanism having means for damping the movement of a carburetor throttle valve and means for preventing running or dieselling of the readily installed in existing engine carburetors.

These and other features and advantages of the pres- Another object of the present invention is to provide ent invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:

FIGS. 1 and 2 are schematic views illustrating a throttlc operating mechanism according to the present invention, the mechanism being shown as incorporated in a conventional carburetor of an internal combustion engine; and

FIGS. 3(A) and (B) are enlarged sectional views illustrating a structural part of the mechanism shown in FIGS. 1 and 2.

Referring now to FIGS. 1 and 2 ofthe drawings, there is shown a throttle operating mechanism implementing the present invention. The throttle operating mechanism proposed by the present invention is used with a conventional carburetor of an internal combustion en- Y 52 extending through a solenoid coil 54 supported by prises a casting 10 in which an air-fuel mixture passage 12 is formed. The air-fuel mixture passage 12 is adapted to communicate with an intake manifold (not shown) of the engine. A throttle'valve 14 is rotatably mounted within the air-fuel mixture'passage 12 for controlling the amount of intake air and accordingly the air-fuel mixture to be fed to the engine cylinders. The throttle valve 14 is fixedly connected to a throttle shaft 16 for rotational movement therewith;

In FIGS. 1 and 2, the throttle operating-mechanism embodying the present invention is shown attached to the carburetor casting l0 and comprises a throttle actuating arm 18 which is rotatably mounted at one end on the throttle shaft 16. The throttle actuating arm 18 has The throttle actuating arm 18 is provided at its other end with a throttle adjusting screw- 22, which is threaded in the arm 18 and held in any adjusted position by a retaining spring 24.

As shown, the throttle operating mechanism further comprises a dashpot, generally designated by reference numeral 26, which has a casing 28 secured to the carburetor casting 10 by some suitable means, though not shown. Diaphragm means such as a flexible diaphragm 30 is disposed in the casing 28 and divides the same into first and second chambers 32 and 34. The first chamber 32 communicates with.the atmosphere through an air vent 38 formed in the casing 28. An actuating. rod 40' is connected to the diaphragm 30 by means of a pair of disc plates 42 .and 44 and extends from the first chamber 32 into the atmosphere through an adjustable guide member 46. Preferably, the actuating rod 40 extends in such a manner that an end 40a of the rod 40 faces an end 22d of the throttle adjusting screw 22. The adjustable guide member 46 is threaded in the bottom part of the casing 28 and held in adjusted position by a nut 48.

As seen, theadjustable guide member 46 has an end portion extending into the first chamber 32 of the casing 28 and, therefore, the disc plate 42 of the dia-.

In FIGS. 1 and 2, the dashpot 26 also includesa second biasing means such as a compressionspring 50,-v which is disposed in the second chamber 34 of thecasing 28 between the diaphragm 30 and a valve plunger the casing 28. The force of second biasing means 50 is determined to be less than that of the first biasing.

means 20 .so that, when thevsolenoidj 'coil 54 is deenergized, the second biasing means 50 is yeilded and therefore the diaphragm 30 is moved to its another ex-- treme position, shown in: FIG. 2 by the action of the first biasing means 20.

The valve plunger 52 is formed at its one end with a tapered valve head 52a which is engageable with a tapered valve surface 56 formed in the casing 28. The valve plunger 52 also has formed therein an axially extending air passage 52)) merging with a laterally extending air passage 520 which opens at the tapered surface of the valve head 52a. Formed at the other end of the valve plunger 52 is an annular flange 52d which serves as a spring seat for the compression spring 50. Indicated by reference numeral. 58 is a covering which is made of resilient material such as rubber. The covering 58 has formed therein an air vent 58a and is tightly fitted on the casing 28 at an upper portion thereof. The

covering 58 also has an opening 58b formed therein through which lead wires 60 extend from the solenoid coil 54. The solenoid coil 54 is grounded through one of the lead wires 60 and is connected through another one of the lead wires 60 to an ignition switch 62, which in turn is connected to a source of electric power supply such as a battery 64. Indicated by reference numeral 66 is an adjustable stop screw which is threaded in a laterally projecting flange 68 and held in any adjusted position by a retaining spring 70. As seen in FIG. 2, the adjustable stop screw 66 is adapted to be engageable at its terminal end with the opposing surface of the actuating lever 18 so that an excessive rotation of the same is prevented,

A's-best seen in FIGS. 3(A) and (B), the disc plate 42 is formed with anaperture 42a which communicates through a variable opening 30a'formed in the flexible diaphragm 30 with an aperture 44a formed in the disc plate 44. Thus, a check valve 72 is formed on the diaphr'agm 30. With this construction, the firstand second chambers 32 and 34 are held in communication with each other through apertures 42a and 44a and the variable opening 30a formed in the disc plates 42 and 44 and diaphragm 30, respectively.

When, in operation, the ignition switch 62 is closed,

" the solenoid coil 54 is energized to cause the valve plunger 52 to be retracted thereby moving the diahragm 30 and accordingly the actuating rod 40 leftwardly as viewed in FIG. 1. Under this circumstance, the valve head 52a of the valve plunger 52 is brought into engagement with the valve surface 56 formed on thccasi'ng 28. Thus, the laterally extending air passage 52c formed in the valve head 52a is presenved from communicating with the air vent 580 formed in the covering 58. During leftward movement of the actuating rod 40, the end a of the actuating rod 40 is brought into engagement-with the end of the throttle adjusting screw 22 thereby rotating the throttle actuating arm 18 counterclockwise-that is, in a direction to slightly open the throttle valve 14 against the action of the first biasing means 20. In this instance, the degree of opening of the throttle valve 14 is determined to have a proper value for effecting easy starting of the engine and for maintaining a desirable idling operation of the engine that is, the rightmost position in which the throttle.

engine intake manifold (not shown) to increase engine speed. It is noticed in this instance that the throttle adjusting screw 22 is brought into disengagement with the end 40a of the actuating rod .40. Under these circumstances, the diaphragm 30 is held in one extreme position, that is, in the leftmost position as viewed in FIG. 1 by the action of the second biasing means 50 disposed between the diaphragm 30 and the spring seat 52d of the valve plunger 52. r As previously mentioned, the valve head 52a of the valve plunger 52 is held in engagement with the valve surface 56 of the casing 28 by the action of the solenoid coil 54 and, therefore, the air passages 52b and 526 formed in the valve plunger 52 is shut off. In this condition, the second chamber 34 is held in communication with the first chamber 32 through the apertures 42a and 44a and the variable opening 30a of the disc plates the first chamber 32 communicates with'the atmosphere through the air vent 38 formed in the casing 28. Under these circumstances, if the accelerator pedal is released to cause deceleration or idling of the engine, the throttle actuating arm 18 is forced to rotate clockwise by the action of the first biasing means 20 thereby to quickly rotate the throttle valve 14 me direction to decrease opening degree. However, upon engagement of the throttle adjusting screw 22 with the end 40a of the actuating rod 40, the speed of rotations of the throttle actuating arm 18 and accordingly the throttle valve 14 is decreased or dampened to effect smooth deceleration of the engine. This is due to the fact that the air passages 52b and 520 of the valve plunger 52 is blockedoff from communicating with the air vent 58a of-the covering 58 while the air in the second chamber 34 expels into the first chamber 32 only through the apertures 42a and 44a and the variable opening 30a of the disc plates 42 and 44 and the diaphragm 30, respectively, in a manner as shown in FIG. 3(A) when the diaphragm 30 is biased in rightward'direction by the action of the first biasing means 20 against the action of the second biasing means 50. Thus, the diaphragm 30 serves as a damping means and gradually moves right- I wardly of the drawing to slowly decrease the throttle opening. This continues until the tension force of the first biasing means 20 balances the compression force of the second biasing means 50.

It is to be noted that the damping effect on the throttle valve movement due to the inherent construction ofthe present mechanism is obtained to provide delayed decrease in the throttle opening during deceleration of the engine and also the engine speed is maintained at a relatively higher level during idling operationof theengine by adjusting the position of the guide 46 and the throttle adjusting screw 22 whereby the quantity of toxic compounds such as hydrocarbons and carbon monoxide contained in the engine exhaust gases is significantly reduced. It is also understood that the mechanism embodying the present invention effect stabilized idling operation of the engine to reduce the above-mentioned toxic compounds in the engine exhaust gases. I

It should be appreciated that if the atmospheric pressure in the second chamber 34 is equalized with that in the first chamber 32 whereas the first biasing means 20 overcomes the force of the second biasing means 50,

the diaphragm 30 is held inits other extreme position,

valve 14 is maintained in a position to have a predetermined opening degree for continuing high-speed idling operation of the engine. If, in this condition, the acceler'ator pedal is depressed, the actuating rod 40 is quickly moved leftwardly of the drawing by the action of the second biasing means 50 as already stated hereinabovev In this instance, the air in the first chamber 32 flows out into the atmosphere through the air vent 38 formed in the casing 28 and is partly delivered into the second chamber 34 through the apertures and opening of the discs and diaphragm disposed therebetween in a manner as shown in FIG. 3(B). Thus, the smooth leftward movement of the actuating rod 40 is obtained.

When, in contrast, the ignition switch 62 is opened,

the solenoid coil 54 is de-energized so that the valve plunger 52 is moved rightwardly of the drawing as shown in FIG. 2 by the action of the second biasing means 50. In this condition, the valve head 52a of the valve plunger 52 is brought into disengagement with the valve surface 56 of the casing 28. Consequently, the air passages 52b and 52c of the valve plunger 52 is brought into communication with the atmosphere through the air vent 58a of the covering 58. Under this circumstance, the second chamber 34 is in communication with the atmosphere and, therefore, the diaphragm 30 is quickly moved rightwardly of the drawing by the force of the first biasing means which is transferred to the throttle actuating rod 18 and to the actuating rod 40 connected to the diaphragm 30. Thereafter, the diaphragm 30 is held in its other extreme position shown in FIG. 2. Thus, the throttle valve 14 is quickly rotated to its closed position so that the engine ceases to operate in the shortest period of time after opening of the ignition switch 62 or the engine is prevented from running off.

It will now be appreciated from the foregoing description that the throttle operating mechanism according'to the present invention has incorporated therein a air passage is opened to release dampening effect thereby to allow quick return of said actuating rod.

2. A throttle operating mechanism as claimed in claim 1, further comprising first biasing means for biasing said throttle actuating arm in a direction to close said carburetor throttle valve, and second biasing means disposed between said diaphragm and said plunger means for biasing said diaphragm and said actuating rod in a direction in which said actuating rod engages said throttle actuating arm.

3. A throttle operating mechanism for a carburetor of an internal combustion engine, comprising a throttle actuating arm rotatable with a carburetor throttle valve, first biasingmeans connected to said throttle actuating arm for biasing thesame in a direction to close said carburetor throttle valve, a casing attached to a carburetor casting, a diaphragm disposed in said casing to define first and second chambers therein and having i said casing, said actuating rod being engageable with an mechanism for damping the movement of the carburetor throttle valve and a valve plunger having an air pas- -plunger to provide a predetermined throttle opening 4 whereas the engine quickly ceases to operate .without running off and accordingly the quantity of the toxic compounds in the engine exhaust gases is reduced.

What is claimed is:

l. A throttle operating mechanism for a carburetor ofan internal combustion engine, comprising a throttle actuating arm rotatable with a carburetor throttle valve to vary throttle opening and biased in a direction to close said carburetor throttle valve, a diaphragm disposed in a casing to define first and second chambers therein and having a check valve providing communication therebetween, an electromagnetically controlled plunger means connected to-one side of said diaphragm and movable therewith, said plunger means having formed therein an air passage communicating with one .of said first and second chambers, and an actuating rod plunger means when the same is moved in one direction whereby movements of said actuating rod and accordingly said diaphragm are dampened whereas, when said plunger means is moved in another direction, said end portion of said throttle actuating arm, a valve plunger disposed in said second chamber of said casing and having formed therein an air passage providing communication between said second chamber'and the atmosphere, said valve plunger also having a valve head engageable with a valve surface formed on said casing, I

an electrically controlledv solenoid coil surrounding said valve'plunger and supported by said casing, and second biasing means disposed between said diaphragmand said valve plunger, said valve plunger being moved against the force of said second biasing means in a direction to cause said valve head to close'said air passage thereby to prevent said second chamber from communicating with atmosphere whereby the atm'ospheric air in said first chamber is allowed into said second chamber through said check valve in said diaphragm for thereby allowing slow movement of said ac tuating rod connected to said diaphragm, and said valve plunger being moved in another direction to open said air passage to provide communication between said second chamber and the atmosphere whereby said threaded in an end portion of said throttle actuating arm, said throttle adjusting screw having an end engageable with an end of said actuating rod.

5. A throttle operating mechanism as claimed in claim 3, further comprising an adjustable guide threaded in said casing and accommodating therein said actuating rod.

6. A throttle operating mechanism as'claimed in claim 3, further comprising an adjustable stop screw threaded in a'laterally extending flange and held in adjusted position to prevent excessive rotation of said throttle actuating arm and accordingly said carburetor throttle valve. 5

7. A throttle operating mechanism'as claimed in claim 3, in which said check valve has apertures formed in disc plates disposed at both sides of, said diaphragm,

and a variable opening formed in said'diaphragm and communicating with said apertures of said discplates. 

1. A throttle operating mechanism for a carburetor of an internal combustion engine, comprising a throttle actuating arm rotatable with a carburetor throttle valve to vary throttle opening and biased in a direction to close said carburetor throttle valve, a diaphragm disposed in a casing to define first and second chambers therein and having a check valve providing communication therebetween, an electromagnetically controlled plunger means connected to one side of said diaphragm and movable therewith, said plunger means having formed therein an air passage communicating with one of said first and second chambers, and an actuating rod connected to the other side of said diaphragm and movable therewith, said throttle actuating arm having an end portion engageable with said actuating rod, said air passage being closed by a valve head formed on said plunger means when the same is moved in one direction whereby movements of said actuating rod and accordingly said diaphragm are dampened whereas, when said plunger means is moved in another direction, said air passage is opened to release dampening effect thereby to allow quick return of said actuating rod.
 2. A throttle operating mechanism as claimed in claim 1, further comprising first biasing means for biasing said throttle actuating arm in a direction to close said carburetor throttle valve, and second biasing means disposed between said diaphragm and said plunger means for biasing said diaphragm and said actuating rod in a direction in which said actuating rod engages said throttle actuating arm.
 3. A throttle operating mechanism for a carburetor of an internal combustion engine, comprising a throttle actuating arm rotatable with a carburetor throttle valve, first biasing means connected to said throttle actuating arm for biasing the same in a direction to close said carburetor throttle valve, a casing attached to a carburetor casting, a diaphragm disposed in said casing to define first and second chambers therein and having check valve providing communication therebetween, said first chamber communicating with the atmosphere, an actuating rod connected to said diaphragm and extending from said first chamber outwardly of said casing, said actuating rod being engageable with an end portion of said throttle actuating arm, a valve plunger disposed in said second chamber of said casing and having formed therein an air passage providing communication between said second chamber and the atmosphere, said valve plunger also having a valve head engageable with a valve surface formed on said casing, an electrically controlled solenoid cOil surrounding said valve plunger and supported by said casing, and second biasing means disposed between said diaphragm and said valve plunger, said valve plunger being moved against the force of said second biasing means in a direction to cause said valve head to close said air passage thereby to prevent said second chamber from communicating with atmosphere whereby the atmospheric air in said first chamber is allowed into said second chamber through said check valve in said diaphragm for thereby allowing slow movement of said actuating rod connected to said diaphragm, and said valve plunger being moved in another direction to open said air passage to provide communication between said second chamber and the atmosphere whereby said actuating rod is allowed to quickly move to a position in which said carburetor throttle valve is closed.
 4. A throttle operating mechanism as claimed in claim 3, further comprising a throttle adjusting screw threaded in an end portion of said throttle actuating arm, said throttle adjusting screw having an end engageable with an end of said actuating rod.
 5. A throttle operating mechanism as claimed in claim 3, further comprising an adjustable guide threaded in said casing and accommodating therein said actuating rod.
 6. A throttle operating mechanism as claimed in claim 3, further comprising an adjustable stop screw threaded in a laterally extending flange and held in adjusted position to prevent excessive rotation of said throttle actuating arm and accordingly said carburetor throttle valve.
 7. A throttle operating mechanism as claimed in claim 3, in which said check valve has apertures formed in disc plates disposed at both sides of said diaphragm, and a variable opening formed in said diaphragm and communicating with said apertures of said disc plates. 